SAT1 Human

What is SAT1 and what are its alternative names in the literature?

SAT1 (Spermidine/spermine N1-acetyltransferase 1) is a rate-limiting enzyme in polyamine catabolism that catalyzes the acetylation of spermidine and spermine. The protein is encoded by the SAT1 gene in humans and may also appear in literature under several alternative names, including Sat, SSAT, SSAT-1, DC21, KFSD, and diamine acetyltransferase 1 . When searching scientific databases, researchers should include these alternative designations to ensure comprehensive retrieval of relevant publications.

What is the basic structure and molecular weight of the SAT1 protein?

The SAT1 protein has a molecular weight of approximately 20 kilodaltons . The protein functions as an acetyltransferase and belongs to the GNAT (GCN5-related N-acetyltransferase) superfamily. SAT1 contains a conserved acetyl-CoA binding domain and forms a homodimeric structure in its functional state. This structural information is crucial for understanding protein-protein interactions and designing structure-based experiments.

In which species are SAT1 orthologs found, and how conserved is the protein?

SAT1 orthologs are found across multiple mammalian species, including canine, porcine, monkey, mouse, and rat . Sequence alignment studies show considerable conservation of catalytic domains across these species, making cross-species research valuable for understanding fundamental SAT1 functions. Mouse models, in particular, have been instrumental in studying the physiological roles of SAT1 in vivo, though researchers should remain attentive to species-specific variations in regulation and function.

What is the primary canonical function of SAT1 in cellular metabolism?

The canonical function of SAT1 is as a rate-limiting enzyme in the catabolic pathway of polyamine metabolism . It catalyzes the acetylation of spermidine and spermine, marking these polyamines for export or oxidation. This regulatory mechanism is crucial for maintaining polyamine homeostasis within cells, affecting numerous cellular processes including proliferation, differentiation, and stress response. Polyamine metabolism studies should consider SAT1 activity as a critical control point in experimental designs.

What noncanonical functions of SAT1 have been discovered in cancer biology?

Recent research has revealed a significant noncanonical role of SAT1 in enabling anchorage-independent cell survival and peritoneal metastasis, particularly in ovarian cancer . Beyond its established function in polyamine metabolism, SAT1 has been found to regulate H3K27ac marks within genes required for mitosis regulation and chromosome segregation . This epigenetic regulatory function affects the expression of critical genes including CCNB1, BUB1B, FANCD2, CENPA, and TOP2A, which are essential for proper mitotic progression and genomic stability . Researchers investigating cancer metastasis should consider incorporating SAT1 analysis in their experimental designs.

How is SAT1 expression regulated under different cellular conditions?

SAT1 expression shows remarkable context-dependency. It is weakly expressed in attached cells but strongly induced upon detachment . This induction is mediated through hypoxia, which typically develops within cell clusters following detachment . Mechanistically, hypoxia-inducible factor-1α (HIF-1α) directly binds to hypoxia response elements (HREs) in the SAT1 promoter region, as confirmed by ChIP assays . Knocking down HIF-1α abrogates SAT1 expression under detached conditions, demonstrating the critical nature of this regulatory pathway . Experimental designs examining SAT1 must account for these microenvironmental influences.

What genomic and epigenomic changes are associated with SAT1 activity?

SAT1 influences the epigenetic landscape by affecting histone modifications, particularly H3K27 acetylation. ChIP-seq analysis revealed that SAT1 knockdown significantly reduces H3K27ac enrichment at promoter regions of genes involved in mitotic cell cycle processes, chromosome organization, and chromosome segregation . This epigenetic regulatory role represents a mechanistic link between SAT1 activity and the transcriptional activation of genes essential for genomic stability and proper cell division. Epigenomic profiling should be considered a valuable approach when investigating SAT1's role in cellular processes.

What antibodies and detection methods are recommended for SAT1 research?

Numerous commercial antibodies are available for SAT1 detection across multiple applications. Researchers have access to at least 216 SAT1 antibodies from 21 different suppliers . When selecting antibodies, consider:

• Application compatibility: Verify validation for your specific application (Western blot, immunoprecipitation, immunofluorescence, etc.)

• Species reactivity: Many antibodies are human-specific, but some cross-react with mouse, rat, or other species

• Clonality: Both monoclonal (e.g., SAT1 D1T7M Rabbit mAb) and polyclonal antibodies are available

• Citation record: Antibodies with published validation data provide higher confidence

For optimal results, researchers should perform their own validation using appropriate positive and negative controls, particularly when studying SAT1 in novel contexts or applying new techniques.

How can researchers effectively study the dual roles of SAT1 in polyamine metabolism and epigenetic regulation?

To comprehensively investigate SAT1's dual functions, researchers should employ a multi-faceted experimental approach:

• For polyamine metabolism:

  • Measure total polyamine content in cells with and without SAT1 manipulation

  • Assess polyamine uptake using radioactive tracers like 3H-putrescine

  • Monitor expression of other polyamine metabolism enzymes to detect compensatory changes

• For epigenetic regulation:

  • Perform ChIP-seq for H3K27ac in SAT1-manipulated cells

  • Validate findings using ChIP-qPCR for specific gene promoters

  • Correlate changes in histone marks with transcriptional changes via RNA-seq or RT-qPCR

  • Conduct rescue experiments through overexpression of affected target genes

This dual analysis enables researchers to determine which SAT1 function predominates in their experimental system.

What experimental models are most suitable for studying SAT1's role in anchorage-independent growth and metastasis?

Based on current research, several experimental models have proven effective:

• In vitro models:

  • Forced detachment assays: Culture cells in ultra-low attachment plates to study anoikis resistance

  • Cell cluster formation: Assess cell aggregation and survival in suspension culture

  • Hypoxia detection: Use fluorescent hypoxia probes (e.g., Image-iT green) to visualize oxygen gradients in 3D cultures

• In vivo models:

  • ID8 peritoneal dissemination model: Particularly useful for ovarian cancer metastasis studies

  • Bioluminescence imaging: Allows longitudinal tracking of tumor growth and spread

  • Ascites formation assessment: Quantify volume and cellular content of ascites fluid

These models should be selected based on the specific research question, with consideration of their respective strengths and limitations.

What are the recommended approaches for manipulating SAT1 expression in experimental systems?

For effective SAT1 manipulation, researchers have successfully employed:

• Knockdown strategies:

  • shRNA: Lentiviral shRNA delivery provides stable long-term knockdown suitable for in vivo studies

  • siRNA: Offers transient knockdown advantageous for acute experiments

• Overexpression approaches:

  • Recombinant SAT1 vectors: Use shRNA-resistant constructs for rescue experiments

  • Inducible systems: Allow temporal control of SAT1 expression

• Validation methods:

  • Western blot: Confirm protein level changes

  • qRT-PCR: Verify transcript level alterations

  • Functional assays: Measure changes in polyamine levels or H3K27ac marks

When designing manipulation experiments, consideration should be given to potential compensatory mechanisms and off-target effects.

How can researchers effectively analyze the impact of SAT1 on cell cycle regulation and genomic stability?

To thoroughly investigate SAT1's effects on mitotic progression and chromosome integrity:

• Cell cycle analysis:

  • Flow cytometry: Combine EdU incorporation with DNA content staining (e.g., Hoechst 33342) to track DNA synthesis and cell cycle distribution

  • Time-lapse imaging: Use fluorescent reporters (mCherry-tubulin, GFP-H2B) to visualize mitotic abnormalities in real-time

• DNA damage assessment:

  • γH2AX detection: Measure levels of this DNA damage marker by flow cytometry or immunofluorescence

  • Comet assay: Quantify DNA strand breaks in individual cells

• Chromosomal stability evaluation:

  • Metaphase spread analysis: Detect chromosomal aberrations and aneuploidy

  • FISH: Identify specific chromosomal abnormalities

These complementary approaches provide comprehensive insight into how SAT1 influences genomic integrity during cell division.

What are the emerging research areas in SAT1 biology that require further investigation?

While significant progress has been made in understanding SAT1's functions, several critical areas warrant focused research:

• Mechanistic studies: The precise molecular mechanism by which SAT1 regulates H3K27 acetylation remains incompletely understood and requires further biochemical characterization.

• Tissue specificity: The differential expression and function of SAT1 across diverse tissue types should be systematically investigated to explain its context-dependent effects.

• Therapeutic targeting: Development of specific SAT1 inhibitors and exploration of their potential in cancer therapy represents a promising avenue, particularly for metastasis prevention.

• Biomarker validation: Larger clinical studies are needed to validate SAT1 as a prognostic biomarker and determine its utility in guiding treatment decisions across different cancer types.